Sony KLV-40W652D-4-blink-error-repair
A Sony LED TV, model KLV-40W652D , arrived at our workshop exhibiting a 4-blink protection error. Here’s a detailed overview of the fault, the diagnostic process, and how the issue was resolved.
Understanding the Fault
The TV displayed a 4-blink protection error, indicating a problem that forced the system into standby mode to avoid further damage.
Observed Behavior: After being turned on, the Sony logo appeared briefly, followed by the TV shifting into protection mode with a repeated 4-blink error code.
Significance: This error suggests an issue with internal voltages or circuitry that the system’s protection mechanism detects as unsafe.
Tracing the Fault
Diagnosing this fault required a systematic approach to check key voltage points within the TV’s circuitry.
Voltage Check
1. Panel Voltage Measurement:
Using a multimeter, the panel VCC voltage was measured. The reading showed a steady 12V, which was within the expected range.
2. Reference Voltage Check:
Further tracing revealed a reference voltage leading to the system IC. This voltage was regulated to 2.1V via a resistor divider network.
Resistor Divider Network
The resistor divider consisted of:
A 10K ohm resistor
A 47K ohm resistor
This network reduces the panel VCC to a stable voltage for the system IC. Faults in these resistors can disrupt the IC’s operation and trigger protection errors.
Fault Identification
Upon closer inspection of the resistor divider network, the issue was pinpointed:
The 10K ohm resistor was faulty, causing instability in the reference voltage.
Replacing this resistor resolved the fault and restored proper function.
Steps Taken:
1. Removed the defective 10K ohm resistor.
2. Replaced it with a new resistor of the same specification.
3. Tested the system after reassembly.
Repair Outcome
Replacing the faulty resistor resolved the issue completely:
The TV powered on without entering protection mode.
The 4-blink error was no longer present, and the TV operated as expected.
Key Takeaways
1. Voltage Stability Is Critical:
Small faults in components like resistors can cause significant system errors.
2. Resistor Divider Importance:
Resistor networks that regulate reference voltages must be in perfect condition to avoid malfunctions.
3. Systematic Diagnosis:
A step-by-step approach to fault tracing helps isolate and fix issues efficiently.
Visual Reference
The location of the faulty resistor is highlighted in the accompanying image (insert image).
Conclusion
Repairing modern LED TVs requires precision and technical expertise. This successful repair of the Sony KLV-40W652D showcases the importance of systematic diagnostics.
For professional Sony LED TV repairs, visit Sony LED TV Repair Center Lahore for expert assistance.
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